DataSync Data Comparison
DataSync determines the difference between the data of two or more terminals in two stages:
Confirming the difference in the number of resources and the last update of the feed.
Finding the difference between the last update of each resource and its lack of - Transmission Control Protocol (TCP) message.
Each User Datagram Protocol (UDP) message stores the name of the feed, the amount of the feed resources and the time of the last update. After the terminal receives a UDP message from the remote terminal, a check is started to compare the data of the two terminals: local and remote. If the data is not equal, then the remote terminal has more recent data and the process of finding the difference is started.
In the mode of finding the difference, the local terminal requests the entire list of resources at the remote terminal and checks for a mismatch of each resource by the time of the last change or the lack of a resource. If a difference is found, the local terminal requests the entity by the identifier of the remote terminal and saves the received data to the POS-APP.